1. Field of the Invention
This invention relates to a receptacle with a closure, having a screw cap with an inner thread and with a guarantee strip without a tear-open tab, which is fastened to the screw cap and is connected via break-off bridge locations, and the receptacle has a cylindrical pour-out with an outer thread in which the screw cap is held.
2. Discussion of Related Art
Screw caps have been known for many years. Their shaping tends to depend on the material from which the receptacle, on which the closure is placed, is manufactured. With glass bottles, the pour-out is usually standardized and the rotary closures must normally correspond to the standard. With receptacles of plastic the pour-out can be more freely varied. Even with receptacles of so-called soft material one applies pour-outs of plastic fastened thereon, which in turn may be manufactured with great freedom with regard to shaping. This invention relates to screw caps which cooperate with receptacles of plastic or soft material, with a pour-out manufactured of plastic and wherein the screw cap and the pour out are matched to one another.
In the present case only screw caps with a guarantee strip which may be opened alone by rotating the screw cap are of interest, wherein simultaneously the guarantee strip is separated from the screw cap. Embodiment forms of such closures are taught by German Patent Reference DE-A-31 11 692, and by European Patent References EP-B-0'149'496, EP-B-0'460'557, EP-B-0'593'396 and EP-B-0'625'950.
The manufacture of such screw caps with a guarantee strip is a problem. On manufacture, the core must be torn out of the screw cap without at the same time the undercuts near the break-off bridge locations leading to the guarantee strips being separated from the screw caps on removal from the mold. The fragile locations are relatively often destroyed during the manufacture and that leads to production interruption and to a rejection of the manufactured closures. In order to reduce a drawback of destruction, there needs to be relatively many break-off locations. Thus, this creates a difficult opening of the screw cap. As known, on screwing open, all break-off locations are uniformly loaded in tension, so that the forces sum and their result is directly related to the number of required break-off locations.
The break-off locations are of course designed extraordinarily thin. The alignment of the molecule chains is thus effected in their region. These molecule chains which are now orientated in the running direction of the break-off webs have their highest resistance force precisely in this running direction. In other words, the forces occurring on screwing open run practically axially to the pour-out direction and thus precisely in the running direction of the break-off locations. Also, it is known that on screwing open, the tension forces are increased relatively slowly, wherein a stretching of material which effects a further alignment of the molecule chains and an increased tear strength.
To reduce the chance of destruction of the guarantee ring or of the guarantee strip on removal from the mold one also applies injection molding tools with sliders. This however leads to extraordinarily expensive tools.
In order to avoid these problems, German Patent Reference DE-A-31 00 629 suggests a screw cap with a guarantee strip with which the guarantee strip is initially integrally formed on the screw cap over the entire wall and the break-off line is only produced retrospectively by way of suitable cutting while leaving the break-off webs. Such closures are considerably easier to open and may be produced with practically no rejects. The manufacture is enormously expensive due to the two-step manufacture. Accordingly, such closures may hardly be obtained in the market.
From the previously discussed closures, it is clear that one may best sever the webs or bridges of the break-off locations between the screw cap and guarantee strip by forces which act in a shearing manner. This principle has only been realized with screw closures on which the guarantee strip is torn away by a tab.